Japanese Patent Application Laid-Open Publication No. 2000-77556 illustrates an embodiment in which a plurality of electrodes formed on a surface of a first circuit substrate and a plurality of electrodes on a second circuit substrate arranged in a semiconductor device are connected using a connector chip constituted by a plurality of spherical balls (BGA ball). At least surfaces of the BGA balls have conductivity, and the BGA balls are respectively fixed to the electrodes of the second circuit substrates arranged in the semiconductor device. Then, the semiconductor device including the BGA balls is arranged at a predetermined location on the first circuit substrate, and the BGA balls are soldered to the corresponding electrodes on the first circuit substrate, respectively. The BGA balls are spherical. Accordingly, when soldering is performed, solder gets into a gap between the spherical surface of each BGA ball and a flat surface of a corresponding one of the electrodes to a satisfactory extent. For this reason, formation of a fillet due to extrusion of the solder from the gap can be prevented. As a result, electrical shorting between the adjoining electrodes among the electrodes caused by soldering can be prevented.    Patent Document 1: Japanese Patent Application Laid-Open Publication No. 2000-77556